308 Prof. Horsford on the Permeability of Metals to Mercury. 
: In the other (b) which was composed of short pieces fused to- 
gether the mercury rose 
In 169 days, m4 BOP 0-224 mm. 
“« A7 days more, . : ‘ OUI = 
“ 53 “c 6c Bs ; 
. 0015 « 
Total, 269 7 0250 « 
Placing these results side by side we have the ascent of’ mer- 
cury in twenty-four ho 
In drawn lead, . ‘ i : 0-070 mm. 
Witist os byron i ; » 0085: “ 
The total height to which the mercury rose during the time of 
experiment 
In drawn lead, = 0143 mm. 
s; Cnet e (a) = 0177 “* 
ce “ (b — 0-250 ce 
The last result confirms a further remark of Prof. Henry, that 
the mercury follows the seams of a cast bar, rather than the more 
homogeneous portions. It is obviously a case of capillary attrac- 
ion, the mercury ascending between the walls of narrow fissures. 
Ill. Does gravity influence the transmission of mercury ? 
Mercury was presented at the top of a bar 0:80 mm. in length. 
though it became saturated discharged no mercury. 
Gravitation evidently facilitates the transmission of the mer- 
cury when flowing from above downwards. It of course op- 
d 
IV. Does the mercury which passes through the bar of lead 
contain the latter metal in solution ? 
V. Is the lead contained in the bar derived from the end of 
the longer leg of the syphon, or from the interior of the bar as 
well as the end? 
In the latter case the interatomic spaces would be increased, 
and the mercury under the inflnence of capillary attraction and 
gravitation, might be expected to flow faster, To ascertain if 
this might be, a syphon bar was arranged, of diameter -0U6 mm. 
—total length one decimetre. The amalgam dropped into @ 
